1. Field of the Invention
The present invention relates to battery packs for power tools and also relates to devices for electrically connecting between batteries and electric circuits of battery packs.
2. Description of the Related Art
A known battery pack includes a case main body with an upper opening, a cover portion for closing the upper opening of the case main body, a plural number of rechargeable batteries stored in the case main body, charge and discharge electric terminals for connecting to a power tool or a battery charger, a control unit for monitoring charge and discharge conditions, and signal lines transmitting the signals from the rechargeable batteries to the control unit. Japanese Laid-Open Patent Publication No. 2002-124306 discloses a technique relating to a battery pack of a type described above. In this publication, the battery pack includes a control unit for monitoring charge and discharge conditions of rechargeable batteries based on voltage signals transmitted from rechargeable batteries. Lead wires are used as signal lines for transmitting the voltage signals of the rechargeable batteries to the control unit.
In order to transmit voltage signals of the plural number of rechargeable batteries to the control unit, a plural number of voluminous lead wires are necessary and thus, a large space is required for wiring. Due to this, the size of the battery pack has become larger.
Therefore, there is a need in the art for preventing enlargement of size of a battery pack by compactly storing a plural number of signal lines in the battery pack.